bug#30073: 27.0.50; dired-do-delete ignores customization for short answers

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Date: Thu, 18 Jan 2018 00:03:04 +0200
> Cc: contovob@tcd.ie, 30073@debbugs.gnu.org,
>       Tino Calancha <tino.calancha@gmail.com>
> 
> But what I'm addressing here in bug#30073 is a regression.

It's not a regression, since we never supported any user-defined
changes to how questions are asked and answered.  Users found a trick
that exploited some internal implementation detail, and used it.  Now
that trick no longer works in this particular case, and new tricks are
needed.

Thus, making the customization "official" in this case is the only way
to "fix" the "regression".

Thanks for working on this.